Incandescent lamp.



No. 883,257. PATENTED MAR. 17, 1908.

' f Mt M. MERRITT.

INCANDBSCENT LAMP.

APPLICATION FILED FEB. l1. 1907.

' Inventor MATTHEW M. MERRiTnoF MiDnLEToN, MASSACHUSETTS, AssiGNoR ToNATIOALEL- y TRIO LAMP COMPANY, OF CLEVELAND, OHIO,

A CORPORATION oF NEW JERSEY.

INCANDESCENT LAMP.

l Specification of Letters latent.

Patent-ed March 17, isos.

Application med February 11, i901. serial No. 356,666.

To all whom 'it may concern:

Be' it'known that I, MATTHEW M. MER-v RITT, a citizen of the UnitedStates, residing at Middleton, county of Essex, and State ofMassachusetts, have invented an Improvement in Incandescent Lamps, ofwhich the following description, in connection with the accompanyingdrawings, is a specification, like letters on the drawings representinglike parts.

My invention relates to incandescent lamps and is `more particularlyconcerned with the production of a new and improved lamp base and anovel process for .the manufacture-of the same. i

My invention will be best understood by reference tothe followingdescription when taken in ,connection with the accompan ing illustrationof one specific embodiment o the same.

In the drawings :hFigure 1 shows in secl tion a form vof mold formolding a dummy or false base .of fusible metal or other like material;Fi 2 shows a like mold where a solid ins ating button is employed forthe tip of the dummy base Fig. 3 shows .a modified form of mold forcasting the metal in the -fornr of an outer shell; Fig. 4-shows thedummy base electro -plated with conductive material; Fig. 5 shows theshell of conductive material with the fusible metal removed; Fi .i 6shows the shell illustrated in Fig. 5 wit an inserted end filling ofinsulatin material; Fig.` 7 shows the completed ase with a strip ofl-conducting material removed from the sides of the insulatingfillinFig. 8 shows a completed base made wit the aid of the false base. shownin Fig. 2, and, Fig. 9 shows a completed lamp having attached thereto abase of the type shown in Fig. 8. i

Referring to the drawings and to the embodiment which I, have thereshown for the illustration ofY my invention, the construcvprinciplesherein described, comprehend tio-nof the lamp base, in accordance withthe generally the reduction of a shel l of conducting material by theelectrolytical depositing of metal upon a core or body of suit" ablyformed filling material, which latter ma afterwards be removed, as byfusion, suc filling materiahby Way of exam le, being of ordinary fusiblemetal fusing at a ow temperatura-or someof the harder waxes, such asparaffin. Such procedure leaves a withdrawn or extracte .y

' of .ready remova type of base now employed, but consisting l of athreaded portion and a tip portion, each consisting of electrolyticallydeposited conducting metal and the two separated by insulatingmaterial.'`

In carryin out my invention I preferably provide a mo d, such as isrepresented in Fig. 1, comprising two split or separated portions 1 and2, which mold is rovided with a recess having the shape of t e desiredlamp bas, and suitably dimensioned to allow mathe subsequenil shrinkageof metal, and the deposition-of copper.w This mold .maybe of any desiredmaterial, such as metal, aper or other suitable substance, and may econstructed in any well-known and usual way, and the shape of the moldmay, of course, be varied to suit the desired requirements andconditions.

Themold having been repared, it is then lled with some materia wliich,`after the deposition 'of Athe 'cop er, may be readil For such materia inthe present instance, I have takena fusible metal, such as babbitt metalhaving a low melted point, forexample at or about 200.

Instead of .fusible metaLfWaX, paraffin or other likey substance may beemployed, er

any substance mayI be used which is capable i This substance whenhardened forms the false or dummy base 3, having finished lamp base.

In order to provide suitable anchorage for the subsequently depositedconducting inaterial, provision of some kind is preferably made. In thedescribed embodiment of my invention the mold is provided near itsbottom with inwardly projecting pins 4 4,

and 'just below the threaded ortions with other pins 5 5, so 'that thefa se base when taken out is revided with correspondi recesses. The aseis then preferably dippe in or coated by some substance which willprevent the copper from clinging to it to'o tenaciously when it isdesired to separate the saine. This substance may be, for ergample,bronze powder orgraphite, which assists the substantially the outline ofAthe metalY in'dropping ,when it `for the falsel or A.For coatingstance,

Ylike-bronze pewderor-'graphite as a prerequisiteto` theel'ectro-platingoperation. f

the baselwith 'metal byA electro: plating, any suitable apparatus 'orprocess` maybe employed. l A large number of bases may be' coated'atvthe sametime by placlng .themlin an electrolytic. bath of suitable.

. nature in'contact with the terminals ofi an bath will ofcourse ofthemet'al electric circuit passing `throughthe bath andA containing abattery or other suitable source of electro-motive force. TThefnatureofthe depend upon the nature which it is desired to` deposit.

If cop er, the usual bath-employed is an represented ture, which, ofcourse,

' ployed in Fig. 5, the same with the inwardly acid so ution ocoppersulfate, but it will be obvious .that nickel, silver or any metalmay beutilized.. VThe bases are sub- 'ected to'A the 'action` of theelectro-plating, ath as long as may be necessary toA secure v-ade ositof conducting material of sufficient esired thickness'fand the latter,when formed, will provide 'a thin,` tenacious skin ofconducting'material. over the exposed por? tions of the false base andconforming `to the irregularities. in the surface of the latter. .Thisleaves a deposit' of copper-'whch is `base indicated at 6in Fig. 4.Having formed* the shell of conducting metalin this fashion,

the false base is withdrawnirom the shell by fusing the same at arelatively low temperacopper for the'shell, which materialhas a'relatively high fusing point. This leaves the shell of conducting.material as represented' being provided, however, directed anchoring.points 7-.7 andA the otheranchoring.- points'` 8.-8..

With the shell formed as shownV in Fig. 5,v the bottom is thenlled orpartly illed with a plug or button 9.of the insulatmg material havingthe axial passage 10 for the -lead wire vof the lam Such .button mayconsist of any desire 4materialand be insertedv in any suitable way, butpreferably the same is fformed of some plastic substance whichcan Ilifefressed in either by hand or b machinery,

l Any desired sub the usual 1withstand the essarily,

esired, and about a suitable orm to leave the passage 10 and thereallowed to harden.

for the insulating plug or button 9, such as the substance shouldpreferably have a heat resistance of not 1essthan400 in order to robablesteps of the lamp manufacture. preferably,.though not nec-v employ somevsubstance which isv plastic at a low temperature, ,but will hardenthrough sta-laag,

- forming /the terminal .desired .removed 1n any by the heavy outhneupon' the has no eect upon theA or other conductingr material ern-fbutton, as representedat 15, Fig. 2.

amel, or vany other-suitable insulating mategiven some suchshape astance may be employed such, for exam.' le, as a mixture of silicatetofsoda, sand an cementL ings-to'act as contacts fior the lead wires theportion 1-1 ofthe metallic shell is then re- -`vmeved from the truncatedcon/ical sideof the insulatingplug 19, leaving thel -iinished base readyfor application to the lamp, as represented at Fig.' 7, the remainingend portion 12` of the shell comprising the. vetallic terminal orcontact for one lead lof the lamp and thethreaded `ortion 13, separatedfrom theend portion yf the insulating plug 9',

or contact for the other lead wire. f a,

PriorY to inserting the insulating lbutton the inner surface of theshell there'at 1s prefer- In order toleave separate'v metallic coatablycoated withsome substance, such, for' example, as collodion, which willassist the copper in separating from the-button when it is removed. Themetal portiony 11 mayv be desired Way and may be ground o fromtheinsulating button or cut away by suitable machinery. n

. AWhen the base is completed, as'shownin Fig. 7, it -will-be seen thatthe anchors 7 ei-` fectively retain the tion rupon y the Yinsulatingshell portion12 in posig'- plug, while the threaded shell portion 113has,- firm engagement chors 8.

`th the plugv by .means of thera'n-v .Instead ofiormingitheins'ulating'v' plug or' button' in the shell as described, apreviously formed button, such as 14 A(Fi .4 2)'-may be placed inthebottom'of lthe mo dwhich latter is shaped accurately to receive'thesame, and the false baseisv then cast on top of this vided between thebutton and the4 fusible metal portion of the base toicause adherencebetweenthetwo. 4 f

Suit- 'I be formed .of any suit# able substance, such` as glass, lava,Vbone', 1

Astone; porcelain, white en'- rial, and may be shown whereby thereisprovided the neck or groove 17 anc-l the smallerxneck or groove 18nearer the tip, these grooves acting effectively to..v anchor thesubseiuently deposited metalA shell theret'o: This lating plated tion 15of `the base meltedjout and the strip of metal overlying the truncatedVconical pori tion 19 v'oi the base cut or ground away.,V as de' v als'ebase with the insui button 14 attached -is then .,electrov as abovedescribed;thefusiblejpor-jlscribed,leaving thenished basek asrepresented in-Figi 8.v u In ordertodiminish the amount of fusible metalrequired, a'core may be em loyed'in connection withthe mold showninlFig.1, so that lthe shellinstead of a solid plug. v Furthermore, if

f'alsebase` is formed in the shape of a be used where a-core 20 ofIabout the sizeof the completed base is used, and a shell 21 of fusiblemetal formed between it and the core. The core is subsequently removedby unscrewing it from the shell 21, the latter then receiving a thincoating of conducting material by electrolytically depositing the samethereon in the manner described. After this conducting shell has beenformed upon the interior of the fusible metal shell, the latter ismelted away as before.

In electro-plating the false baseshown in Fig. 2 it will be understood,of course, that the insulating button is coated with graphite or bronzepowder before being placed in the electrolytic bath in order that thedeposit of copper may take place upon its entire surface. If desired,instead of cutting awaythe strip or area of metal interveninor betweenthe two terminall contacts of the tlamp, the metal may be deposited, inthe first instance, upon separated areas, if desired, by omitting thecoating of bronze powder or other conducting material along the portion19 of the button, or wherever the deposit of metal is not required.Thesame result may be accomplished in the forming of the base shown inFigs. 1, 4, 5,-6, and 7 by coating over the portion 11 of the base,where no 'deposit of copper is required, with some insulating substanceIsuch as wax or araffin.

The base after comp etion may be a plied to the lamp in any desired way,such, or example, as is shown in Fig. 9, where it is cemented thereto bya body 22 of cementitious material lconsisting of plaster, cement, orany other suitable substance, the lead wires being secured to the endcontacts and the threaded shell portion, respectively, in the mannerabove described.

. A shell for the base of an incandescent lamp constructed as definedherein has many physical characteristics whereby it may be distinguishedfrom a shell or sleeve of material such as shown in the prior art. It isnecessary in the formation of the screw threads shown in the referencesto resort to a spinning operation by which the material is compacted orcompressed -and thus rendered more dense at the points operated upon insuch spinning operation. A shell constructed in accordance with myinvention may be of uniform density throughout. Thespinning operationreferred to s reads the metal and as it draws the ducti ity thereof, thecompleted product has remaining a less degree of ductility in the spunortion than any portion not spun. herein defined, all portions may be ofequal ductility and in no portion thereof is the metal artificiallyspread or compacted. Moreover, in the prior art, it is necessary thatall portions of the shell, includin0r "the threaded portion, be smooth.In a shellconstructed as herein defined, I may render the In a she lconstructed asl threaded portion smooth and may provide irregularitlesvor anchoring conformations upon the portion thereof that is in contactwith the plug or button 9 if desired. Furthermore, that portion oftheshell vthat is in contact with the button conforms to allirregularities', whether natural or otherwise, of

such plug or button and may even penetrate the larger pores thereof. Inother words, the surface character of the threaded portion of the shell,when constructed in accordance with my invention, may if desired besimilar to or it may be differentiated from that of the ortion of theshell that contacts with the p ug or button. It may also be stated thatthe shell, when constructed inaccordance with the present disclosure,vmay be of exceeding thinness, so as to be' truly defined as a iiIm ormembrane or on the other hand of considerable thickness if desired.

form of my invention and one mode of carrying the same into effect, itis to be understood that thesame is not limited to the details ofconstruction here described or to the Vexact steps of the process hereinset forth, but that extensive modifications therein may be made Withoutdeparting from the spirit of the invention.

Claims. 'i

1. An incandescent lamp having a bulb and a base ortion. the lattercomprising a thin shell of) electrolytically deposited conductivematerial in which the neck of said bulb is secured by an interveningbody of cem- -entitious material, said shell having threaded sides toadapt it to fit a threaded lamp holding socket, a body of insulatingmateria at the bottom of said shell, the end of the lat-l l ter beingsecured by physical adherence to the adjacent surface of saidinsulatingbody and conforming to the contour and `irregularities of thesurface thereof, conductive material secured to the tip end of saidinsulating.`

body, but separated from the threaded shel by the intervening andexposed surface of said insulating body, and lamp terminals connectedone to said shell and the other to the conductive material at the tip ofsaid insulating body. f

2. As a new article of manufacture, an incandescent lam base comprisinga thin shell of electrolyticafiy deposited conductive TIiaterial inwhich the neck'of an incandescent 1am bulb is ada ted to be secured,said shell) having threaded sides to iit a threaded lamp holding socket,a body of insulatin material at the bottom of said shell, the en of thelatter being secured b physical adhesion to the outersurface ofy bodythereby to conform to the contour an irregularities thereof forreventing'ldisplacement thereof and con uctive material secured to thetip end of said body, but separated from said threaded shell by anintersaid insulating.

Y. body.

` `for incandescent lamp bulbs,

Vbody 9 of insulatin outer surface of said insulating bod forming to-the contour and irreguarities- 4shell extending to present veningandexposed surface of said insulating a new article of manufacture, a basecomprising a material, a thin shell 13 eposited conductive maadherence:to the conof electrolytically terial secured by physical Vthe said tipof said insnlatin shell of electrolytic'allyvdeposited cond'uctivematerial'in Awhich the sides to vadapt it to itathrea neck of the bulbis secured; said shell having threaded A ded ampl hold-e 25 ingsocket,there being abody'of insulating material `connected to said;shell,fconduetive material secured to the tip-end of said insulatinmaterial, but separated [from the Athreaded shell'b'y the interveningand. ex

osed surface ofsald insulating material, and amp terminals connectedoneto said shellr and the other to the conductive material at body.

In testimony whereof, I ave Signed my 35 name to this speciiication, in'the presence of tWo subscribing Witnesses.

y lvrERRITT.

Witnesses: I y Y i' YWALTER J. LANE,

THOMAS B'.BooTH.

